Grass endophytes for insect management

and improved pasture productivity

John Caradus

On behalf of a very big team of people

Content

1. What are fungal endophytes?

2. What is the biocontrol issue?

3. What has been achieved?

4. How was this achieved?

5. What is next – other uses of endophytes?

1. What are fungal endophytes?

Fungal endophyte + Grass Plant

Endo = within - Phyte = plant

Each green dot is a hypha of an endophyte expressing

a green florescent protein

Endophyte lifecycle

Diversity in endophytes

• Neotyphodium fungal endophytes are not all the same, there is considerable diversity in their biochemical profiles

• Europe has a wide diversity of grass endophytes

• AgResearch has the largest collection of grass

endophytes in the world

• New Zealand is the recognised world leader in

grass endophyte technology and its

commercialisation

What fungal endophytes do ?

• Protect host plants against biotic and abiotic stresses

• Biotic stress protection

– Insects

– Nematodes

– Plant pathogens

• Abiotic stress protection

– Drought

• Protection increases plant production and persistence

Endophyte chemistry

• Endophytes are all about chemistry

• They produce a range of bioactive

secondary metabolites (alkaloids)

• The type of alkaloids produced depends

on the strain of fungus present

• The host plant has a major effect on the

quantity of alkaloids

• The chemistry of endophytes is diverse

and complex

Endophyte alkaloids

• Four main groups identified

– Peramine

– Ergovaline

– Indole diterpenoids

• Lolitrems

• Epoxy janthitrems

– Lolines

• All are active against insects

– Toxic

– Deterrent

• Unknowns

Basic science

• Understanding the life cycle of Neotyphodium

endophytes

• Isolation from grasses and growth ex plant

• Inoculations challenges – into the plant

• Transmission challenges – into the seed

• Understanding the chemistry – discovering

unknown alkaloids

• Understanding the genes controlling alkaloid

expression

• Endophyte viability in seed

2. What is the biocontrol issue?

Pests of endophyte-free ryegrass

• Porina

• African black beetle

• Argentine stem weevil

• Pasture mealy bug

• Grass grub

• Root aphid

Ryegrass + Endophyte Ryegrass – Endophyte

Meadow fescue + Endo Meadow fescue – Endo

Tall fescue + with Endophyte Tall fescue – minus Endophyte

Tall fescue at Bega, NSW, Australia

But….

• While endophytes alkaloids do have powerful

insecticidal properties some can also have

serious affects on ruminants

Ergovaline - a vaso-constrictor that causes heat stress,

and reduces live weight gains and serum prolactin

Lolitrem B - a tremorgen that causes the neuro-muscular

disorder ryegrass staggers

Epoxy janthitrems - a tremorgen

• It is a case of balancing the upside of insect

resistance with the downside of animal health

and welfare

Ryegrass staggers!

3. What has been achieved?

Tall FescueEndophytes

Ryegrass Endophytes

ENDO 5

1

Timeline for

ryegrass endophyte

understanding and

development

Endophyte linked with

- insect resistance

- ryegrass staggers, then production

1980

1992 First novel endophyte released –partially withdrawn

AR1 novel endophyte2000

2007 AR37 novel endophyte

2010 >80% seed sales of proprietary cultivars have novel endophytes

1980 - 90 Development of High Endophyte lines (containing a wild-type endophyte)

2003 NEA2 novel endophyte

2011- 2020 Novel endophytes with better insect resistance and drought tolerance

2006 Endo5 novel endophyte

Ryegrass endophyte

1

AR1 endophyte

• Ryegrass endophyte that does not cause

ryegrass staggers but provides Argentine stem

weevil resistance

• Non-exclusive release

• Initially targeted for Australasia

• Uptake rate has been high

AR1 - Pastoral industry benefits

AR1 a technological breakthrough

Prevents ryegrass staggers

Does not cause heat stress

Reduces fly strike

Increases live weight gain >10%

Increases milk solids 9%

Lamb responses to grazing Nui ryegrass with AR1

endophyte in summer and autumn. Means of 3 years

Values within a column with a letter subscript in common are not significantly different

* LWG = Live weight gain, Resp = respiration, PRL = prolactin, RGS = ryegrass staggers

Ryegrass

cultivar +

endophyte:

LWG *

g/hd/day

Rectal

tempO C

Resp

rate

/min

PRL

Ng/ml

RGS

0-5

scale

Dags

0-5

scale

Nui wild-type 23 a 40.5 a 97 a 96 a 3.2 a 0.6 a

Nui nil 120 b 40.0 b 73 b 185 b 0 b 0.2 b

Nui AR1 131 b 40.1 b 79 b 203 b 0 b 0.3 b

Ryegrass endophyte

37

AR37

Aorangi (Manawatu) April 1999

AR37(left) versus existing pasture

Photo taken at AgResearch Farm at Tokonui - 29 February 2008

Comparisons

AR37AR1

StandardEndophyte-free

Argentine stem weevil

Manawatu Kerikeri Waikato

Nil 20 36 63

AR1 8 6 17

AR37 4 4 18

Standard 7 5 28

P<0.05 P<0.05 P<0.05

National Evaluation Field Trials 1997 & 1998

Percent tillers with larval damage

Black Beetle - Larval Numbers

0

20

40

60

80

100

120

140

No

. la

rvae/m

2

Nil Std AR37AR1 Nil Std AR37AR1

Year 1 Year 2

Porina – Plant Damage

0

2

4

6

8

10

12

14

2 4 6

Week

Cu

mu

lati

ve d

am

ag

e

Nil Standard AR37

0

5

10

15

20

25

1 2 3 4 5

Week

Nil Standard AR37

Trial 1 Trial 2

Pasture Mealy bug – Field Trial

0

2

4

6

8

10

12

14

16

18N

o.

mealy

bu

g/c

ore

Nil Std AR37 AR1

Root Aphids – Pot Trial

0

50

100

150

200

250

300

Mean

No

./P

lan

t

April Sept Jan May

Nil Standard AR37

Issues with AR37

• Grass staggers can be experienced with AR37 –

these are short lived and not normally as severe

as those experienced on wild type endophyte.

Recommendation:

• If AR1 persists on your farm then sow AR1

• If AR1 does not persist then sow AR37 – not

high endophyte wild type.

Tall fescue Endophyte

Case study – into the USA

Fescue toxicosis in cows - caused by

toxic endophytePregnancy rate reduced up to 37%

Abortion during early pregnancy

Calf deaths up to 20% after birth

Calving reduced from 78-95% to 49-74%

Intolerant to heat

Grazing time reduced 20 - 90%

Forage intake reduced 40%

Milk production reduced 37 - 60%

Weaning weights of calves reduced 14%

Endophyte-infected tall fescue can

cause serious problems with cattle

The alkaloid ergovaline results in damaging

elevated body temperatures

MaxQ endophyte

• Tall fescue non-toxic endophyte identified

for USA

• Patent protection of IP

• Exclusive license for defined period

• Marketing as an added value products

• Improved plant persistence without

causing any adverse animal effects

No

endophyteMaxP MaxP

The benefits of MaxQ

• Compared to Kentucky 31 (contains toxic endophyte) tall

fescue pastures in USA, the benefits of MaxQ pastures for

pasture-finished beef are:

Removes toxic alkaloids from meat and fat

Increases calf numbers (+ 20 to 50 %)

Increases milk production

Increases weaning weights (+ 15 %)

Reduced number of days for steers to reach target weights (- 60%)

Heavier live weight of feeder cattle per acre (+ 140%)

Heavier carcass weights (+ 10%)

Increased value of beef produced (+ 9%)

Wild, toxic endophyte in

Jesup TALL FESCUEAR542 endophyte in

Jesup TALL FESCUE

Lamb Safety Study at Eatonton, Georgia, USA

4. How was all of this achieved?

+

Understanding the process

Grass

Fungus

Chemistry

Insects

Successful ingredients

• A great R&D team – multi-disciplined approach

and very good science

• Strong international links

• Strong links to NZ industry – supported

financially by seed companies and Beef and

Lamb (when it was Meat and Wool)

• Strong commercialisation drive through

Grasslanz Technology Ltd and commercial

partners

The Grass Endophyte R&D Team

• Garry Latch

• Mike Christensen

• Syd Easton

• David Hume

• Alison Popay

• Brain Tapper

• Lester Fletcher

• Sarah Finch

• Wade Mace

• Chris Pennell

• Geoff Lane

• Lynn Briggs

• Wayne Simpson

• Stuart Card

• Phil Rolston

• Lee Sutherland

• Bruce Cooper

• Jason Trethewey

• Heike Schwendel

• Marty Faville

• Jana Schmidt

• Anouck de Bonth

• Joanne Jensen

• And others

Mycologists

Animal scientists

Seed scientists

Agronomists

Chemists

Plant scientists

Entomologists

Endophyte

Knowledge

Multidisciplinary

approach

5. What is next – other uses of

endophytes?

Current opportunities

• Wildlife deterrence

• Endophyte in cereals

• Pesticidal extract

Cafeteria Seed Feeding

0

10

20

30

40

50

60

70

80

90

100

NIL ENDO NOVEL A NOVEL B

Treatments

Gra

ms

Co

ns

um

ed

“Learned geese”

Aphids on roses

Natural pesticide treated Control

Fungal endophytes

• A very successful method of biocontrol that is

seed transmitted

• Based on excellent science

• Commercially successful and is being widely

used

With endophyte Without endophyte